A preliminary study involving 254 nm irradiation of dichloromethane suspension containing TiMCM-41 catalyst and meso-tetraphenylporphyrin (TPP) was carried out at pH 5.0. The rate of the photoreaction was considerably increased in the presence of the catalyst. Increasing the amount of the catalyst at a fixed TPP concentration enhances the rate, indicating its catalytic role in the reaction. The effect of pH, TPP concentration and calcination temperature of the catalyst on the photoreaction was also investigated. (C) 2000 .